Re: [PATCH 1/8] drm: bridge: Add support for static image formats

From: jacopo mondi
Date: Thu Apr 26 2018 - 14:44:50 EST


Hi Peter,

On Sun, Apr 22, 2018 at 10:02:23PM +0200, Peter Rosin wrote:
> On 2018-04-19 11:31, Jacopo Mondi wrote:
> > Add support for storing image format information in DRM bridges with
> > associated helper function.
> >
> > This patch replicates for bridges what 'drm_display_info_set_bus_formats()'
> > is for connectors.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/drm_bridge.c | 30 ++++++++++++++++++++++++++++++
> > include/drm/drm_bridge.h | 8 ++++++++
> > 2 files changed, 38 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index 1638bfe..e2ad098 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -157,6 +157,36 @@ void drm_bridge_detach(struct drm_bridge *bridge)
> > }
> >
> > /**
> > + * drm_bridge_set_bus_formats() - set bridge supported image formats
> > + * @bridge: the bridge to set image formats in
> > + * @formats: array of MEDIA_BUS_FMT\_ supported image formats
> > + * @num_formats: number of elements in the @formats array
> > + *
> > + * Store a list of supported image formats in a bridge.
> > + * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
> > + * a full list of available formats.
> > + */
> > +int drm_bridge_set_bus_formats(struct drm_bridge *bridge, const u32 *formats,
> > + unsigned int num_formats)
> > +{
> > + u32 *fmts;
> > +
> > + if (!formats || !num_formats)
> > + return -EINVAL;
>
> I see no compelling reason to forbid restoring the number of reported
> input formats to zero? I can't think of a use right now of course, but it
> seems a bit odd all the same.

It is, you're right. Will fix in v2 and will allow bridges to just
restore formats to 0 (as it is done for drm_connectors, by the way)

Thanks
j
>
> Cheers,
> Peter
>
> > +
> > + fmts = kmemdup(formats, sizeof(*formats) * num_formats, GFP_KERNEL);
> > + if (!fmts)
> > + return -ENOMEM;
> > +
> > + kfree(bridge->bus_formats);
> > + bridge->bus_formats = fmts;
> > + bridge->num_bus_formats = num_formats;
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(drm_bridge_set_bus_formats);
> > +
> > +/**
> > * DOC: bridge callbacks
> > *
> > * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
> > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> > index 3270fec..6b3648c 100644
> > --- a/include/drm/drm_bridge.h
> > +++ b/include/drm/drm_bridge.h
> > @@ -258,6 +258,9 @@ struct drm_bridge_timings {
> > * @encoder: encoder to which this bridge is connected
> > * @next: the next bridge in the encoder chain
> > * @of_node: device node pointer to the bridge
> > + * @bus_formats: wire image formats. Array of @num_bus_formats MEDIA_BUS_FMT\_
> > + * elements
> > + * @num_bus_formats: size of @bus_formats array
> > * @list: to keep track of all added bridges
> > * @timings: the timing specification for the bridge, if any (may
> > * be NULL)
> > @@ -271,6 +274,9 @@ struct drm_bridge {
> > #ifdef CONFIG_OF
> > struct device_node *of_node;
> > #endif
> > + const u32 *bus_formats;
> > + unsigned int num_bus_formats;
> > +
> > struct list_head list;
> > const struct drm_bridge_timings *timings;
> >
> > @@ -296,6 +302,8 @@ void drm_bridge_mode_set(struct drm_bridge *bridge,
> > struct drm_display_mode *adjusted_mode);
> > void drm_bridge_pre_enable(struct drm_bridge *bridge);
> > void drm_bridge_enable(struct drm_bridge *bridge);
> > +int drm_bridge_set_bus_formats(struct drm_bridge *bridge, const u32 *fmts,
> > + unsigned int num_fmts);
> >
> > #ifdef CONFIG_DRM_PANEL_BRIDGE
> > struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
> >
>

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